Spooks

Poltergeist, from the German words polter, meaning noise, and geist, meaning spirit, is a supposed kind of ghost that, as its name implies, allegedly causes unexplained noises such as banging on a wall, footsteps on a floor, slamming doors, even throwing things. Some have even allegedly pushed, struck or otherwise assaulted people. Reports of them have been made for centuries. While many, or most, can simply be explained by natural causes, mental illness of the "witness," honest misperception, or outright fraud, others have not been accounted for.

Do "Ghosts" Really Exist?

The Bible plainly states that the spirit world is teeming with life. God Himself of course is Spirit. The Holy Spirit of God (called the "Holy Ghost" in earlier translations of the Bible, see The Holy Ghost and The Holy Spirit) is Spirit. God also created countless billions of angels, the good ones being the servants of Believers (e.g. "Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?" Hebrews 1:14 KJV), but there are also angels who rebelled and sinned, known now as demons (or "devils" in older translations; see also What Makes Satan A Devil?). The chief among these is Satan himself who became a wicked rebel (see Born To Be Wild? and What Does Satan Look Like?)

But what are "ghosts"? Are they angels of some sort? Or are they spirits of humans who have died?

There is only one recorded incident in the Scriptures of the spirit of a dead human seeming to appear to someone, that of Samuel appearing to Saul. It's important to note that, if it was somehow actually the awakened spirit of Samuel, as it seems to have been, the rare incident was to deliver a Godly message, not to scare or haunt anyone:

"And the king said unto her, Be not afraid: for what sawest thou?"

"And the woman said unto Saul, I saw gods [or a spirit NIV] ascending out of the earth."

"And he said unto her, What form is he of?"

"And she said, An old man cometh up; and he is covered with a mantle."

"And Saul perceived that it was Samuel, and he stooped with his face to the ground, and bowed himself."

"And Saul answered, I am sore distressed; for the Philistines make war against me, and God is departed from me, and answereth me no more, neither by prophets, nor by dreams: therefore I have called thee, that thou mayest make known unto me what I shall do."

"Then said Samuel, Wherefore then dost thou ask of me, seeing The Lord is departed from thee, and is become thine enemy? And The Lord hath done to him, as he spake by me: for The Lord hath rent the kingdom out of thine hand, and given it to thy neighbour, even to David: Because thou obeyedst not the voice of The Lord, nor executedst his fierce wrath upon Amalek, therefore hath The Lord done this thing unto thee this day. Moreover The Lord will also deliver Israel with thee into the hand of the Philistines: and to morrow shalt thou and thy sons be with me: The Lord also shall deliver the host of Israel into the hand of the Philistines."

"Then Saul fell straightway all along on the earth, and was sore afraid, because of the words of Samuel: and there was no strength in him; for he had eaten no bread all the day, nor all the night." (1 Samuel 28:13-20 KJV)

It's also very important to note that Saul used a witch (1 Samuel 28:7) to consult that spirit, something that God commanded never to do:

"There shall not be found among you any one that maketh his son or his daughter to pass through the fire, or that useth divination, or an observer of times, or an enchanter, or a witch, Or a charmer, or a consulter with familiar spirits, or a wizard, or a necromancer. For all that do these things are an abomination unto The Lord: and because of these abominations The Lord thy God doth drive them out from before thee." (Deuteronomy 18:10-12 KJV)

Are ghosts angels then? Righteous angels did appear to humans quite often throughout Bible History, but they never did it in a "haunting" or obscure manner. They usually appeared in the form of humans, who identified themselves in a clear and dignified manner, while bringing a message or on a mission from God. There was no nonsense.

Demons are fallen angels who have become warped in thought and behavior. The very small number of "unexplainable" incidents (keeping in mind that most sightings are honest misperceptions, deliberate fabrications, or unhealthy delusions by the mentally ill or those impaired by alcohol or drugs) are very likely demons. And they are nothing to worry about for the converted Christian.